The conventional tractor assembly is designed to be operated and to move the wheel chair by the disable person sitting in the wheel chair. The tractor assembly is compact and easily connected to the wheel chair. However, the conventional tractor assemblies usually are heavy and take a lot of steps to be connected to or dis-connected from the wheel chair. Some of the conventional tractor assemblies are not stable.
The conventional tractor assemblies usually require a special designed device to be connected to the wheel chair before the tractor assembly is able to be connected to the wheel chair, and the special designed device increases the weight of the whole assembly and involves extra assembling steps. Besides, the special designed device cannot be automatically connected to the wheel chair, so that the disable person has to ask for assistance when connecting or dis-connecting the tractor assembly. In addition, the conventional tractor assemblies are expensive so that most of the disable persons cannot afford the tractor assembly. Although the conventional tractor assemblies have support legs so that the tractor assembly can be installed and assembled in the upright position, however, the hanger brackets of the wheel chair have to be removed before installing the tractor assembly to the wheel chair.